NeuroPace (NPCE) 10-Q 12 Nov 24 2024 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2024	Nov. 07, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-40337
Entity Registrant Name	NEUROPACE, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-3550230
Entity Address, Address Line One	455 N. Bernardo Avenue
Entity Address, City or Town	Mountain View
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94043
City Area Code	650
Local Phone Number	237-2700
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	NPCE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		29,848,101
Amendment Flag	false
Entity Central Index Key	0001528287
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3

Condensed Balance Sheets (unaud

Condensed Balance Sheets (unaudited) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 15,418	$ 18,058
Short-term investments	41,412	48,396
Accounts receivable	11,561	12,314
Inventory	12,084	11,214
Prepaid expenses and other current assets	2,116	2,737
Total current assets	82,591	92,719
Property and equipment, net	1,041	1,003
Operating lease right-of-use asset	12,246	13,405
Restricted cash	122	122
Deferred offering costs	288	387
Other assets	15	15
Total assets	96,303	107,651
Current liabilities
Accounts payable	2,160	2,332
Accrued liabilities	10,072	11,180
Operating lease liability	1,800	1,627
Deferred revenue	749	1,090
Total current liabilities	14,781	16,229
Long-term debt	59,266	56,954
Operating lease liability, net of current portion	12,433	13,814
Total liabilities	86,480	86,997
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, $0.001 par value, 10,000,000 shares authorized and no shares issued and outstanding as of September 30, 2024 and December 31, 2023	0	0
Common stock, $0.001 par value, 200,000,000 shares authorized as of September 30, 2024 and December 31, 2023; 29,777,966 and 27,823,465 shares issued and outstanding as of September 30, 2024 and December 31, 2023, respectively	30	28
Additional paid-in capital	535,493	524,435
Accumulated deficit	(525,700)	(503,809)
Total stockholders’ equity	9,823	20,654
Total liabilities and stockholders’ equity	$ 96,303	$ 107,651

Condensed Balance Sheets (una_2

Condensed Balance Sheets (unaudited) (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock shares authorized (in shares)	10,000,000	10,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	200,000,000	200,000,000
Common stock issued (in shares)	29,777,966	27,823,465
Common stock outstanding (in shares)	29,777,966	27,823,465

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Revenue	$ 21,060	$ 16,427	$ 58,440	$ 47,409
Cost of goods sold	5,640	4,194	15,543	12,832
Gross profit	15,420	12,233	42,897	34,577
Operating expenses
Research and development	5,754	4,795	17,603	15,401
Selling, general and administrative	13,909	13,388	43,312	41,299
Total operating expenses	19,663	18,183	60,915	56,700
Loss from operations	(4,243)	(5,950)	(18,018)	(22,123)
Interest income	754	769	2,343	2,228
Interest expense	(2,182)	(2,191)	(6,606)	(6,281)
Other income (expense), net	219	115	390	(580)
Net loss and comprehensive loss	$ (5,452)	$ (7,257)	$ (21,891)	$ (26,756)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.19)	$ (0.28)	$ (0.76)	$ (1.05)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.19)	$ (0.28)	$ (0.76)	$ (1.05)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic (in shares)	29,444,625	26,017,329	28,863,120	25,532,415
Weighted-average shares used in computing net loss per share attributable to common stockholders, diluted (in shares)	29,444,625	26,017,329	28,863,120	25,532,415

Condensed Statements of Stockho

Condensed Statements of Stockholders’ Equity (unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022		25,045,751
Beginning balance at Dec. 31, 2022	$ 34,777	$ 25	$ 506,713	$ (1,108)	$ (470,853)
Increase (Decrease) in Stockholders' Equity
Net loss	(10,375)				(10,375)
Unrealized loss adjustment for short-term investment	1,108			1,108
Issuance of common stock pursuant to stock option exercises (in shares)		17,608
Issuance of common stock pursuant to stock option exercises	1		1
Issuance of common stock upon vesting of restricted stock units (in shares)		325,747
Shares withheld for taxes (in shares)		(35,562)
Shares withheld for taxes	(146)		(146)
Repurchase of common stock (in shares)		(1,340)
Stock-based compensation	2,125		2,125
Ending balance (in shares) at Mar. 31, 2023		25,352,204
Ending balance at Mar. 31, 2023	27,490	$ 25	508,693	0	(481,228)
Beginning balance (in shares) at Dec. 31, 2022		25,045,751
Beginning balance at Dec. 31, 2022	34,777	$ 25	506,713	(1,108)	(470,853)
Increase (Decrease) in Stockholders' Equity
Net loss	(26,756)
Ending balance (in shares) at Sep. 30, 2023		26,244,935
Ending balance at Sep. 30, 2023	16,363	$ 26	513,946	0	(497,609)
Beginning balance (in shares) at Mar. 31, 2023		25,352,204
Beginning balance at Mar. 31, 2023	27,490	$ 25	508,693	0	(481,228)
Increase (Decrease) in Stockholders' Equity
Net loss	(9,124)				(9,124)
Issuance of common stock pursuant to stock option exercises (in shares)		164,134
Issuance of common stock pursuant to stock option exercises	5	$ 1	4
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		164,710
Issuance of common stock pursuant to Employee Stock Purchase Plan	240		240
Issuance of common stock upon vesting of restricted stock units (in shares)		145,787
Shares withheld for taxes (in shares)		(9,906)
Shares withheld for taxes	(41)		(41)
Change in early exercise liability	1		1
Stock-based compensation	2,655		2,655
Ending balance (in shares) at Jun. 30, 2023		25,816,929
Ending balance at Jun. 30, 2023	21,226	$ 26	511,552	0	(490,352)
Increase (Decrease) in Stockholders' Equity
Net loss	(7,257)				(7,257)
Issuance of common stock pursuant to stock option exercises (in shares)		313,107
Issuance of common stock pursuant to stock option exercises	8		8
Issuance of common stock upon vesting of restricted stock units (in shares)		119,164
Shares withheld for taxes (in shares)		(4,265)
Shares withheld for taxes	(35)		(35)
Stock-based compensation	2,421		2,421
Ending balance (in shares) at Sep. 30, 2023		26,244,935
Ending balance at Sep. 30, 2023	$ 16,363	$ 26	513,946	$ 0	(497,609)
Beginning balance (in shares) at Dec. 31, 2023	27,823,465	27,823,465
Beginning balance at Dec. 31, 2023	$ 20,654	$ 28	524,435		(503,809)
Increase (Decrease) in Stockholders' Equity
Net loss	(8,925)				(8,925)
Issuance of common stock pursuant to stock option exercises (in shares)		409,045
Issuance of common stock pursuant to stock option exercises	721		721
Issuance of common stock upon vesting of restricted stock units (in shares)		522,483
Issuance of common stock upon vesting of restricted stock units	0	$ 1	(1)
Shares withheld for taxes (in shares)		(37,541)
Shares withheld for taxes	(649)		(649)
Stock-based compensation	2,540		2,540
Ending balance (in shares) at Mar. 31, 2024		28,717,452
Ending balance at Mar. 31, 2024	$ 14,341	$ 29	527,046		(512,734)
Beginning balance (in shares) at Dec. 31, 2023	27,823,465	27,823,465
Beginning balance at Dec. 31, 2023	$ 20,654	$ 28	524,435		(503,809)
Increase (Decrease) in Stockholders' Equity
Net loss	$ (21,891)
Issuance of common stock pursuant to stock option exercises (in shares)	519,314
Ending balance (in shares) at Sep. 30, 2024	29,777,966	29,777,966
Ending balance at Sep. 30, 2024	$ 9,823	$ 30	535,493		(525,700)
Beginning balance (in shares) at Mar. 31, 2024		28,717,452
Beginning balance at Mar. 31, 2024	14,341	$ 29	527,046		(512,734)
Increase (Decrease) in Stockholders' Equity
Net loss	(7,514)				(7,514)
Issuance of common stock pursuant to stock option exercises (in shares)		95,008
Issuance of common stock pursuant to stock option exercises	53		53
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		94,743
Issuance of common stock pursuant to Employee Stock Purchase Plan	528		528
Issuance of common stock upon vesting of restricted stock units (in shares)		242,518
Shares withheld for taxes (in shares)		(9,233)
Shares withheld for taxes	(72)		(72)
Repurchase of common stock (in shares)		(1,282)
Change in early exercise liability	1		1
Stock-based compensation	2,548		2,548
Ending balance (in shares) at Jun. 30, 2024		29,139,206
Ending balance at Jun. 30, 2024	9,885	$ 29	530,104		(520,248)
Increase (Decrease) in Stockholders' Equity
Net loss	(5,452)				(5,452)
Issuance of common stock pursuant to stock option exercises (in shares)		15,261
Issuance of common stock pursuant to stock option exercises	34		34
Issuance of common stock as part of At-the-Market offering, net of issuance costs of $189 (in shares)		413,988
Issuance of common stock as part of At-the-Market offering, net of sales commission and offering expenses of $189	2,833	$ 1	2,832
Issuance of common stock upon vesting of restricted stock units (in shares)		218,743
Issuance of common stock upon vesting of restricted stock units	0
Shares withheld for taxes (in shares)		(9,232)
Shares withheld for taxes	(68)		(68)
Stock-based compensation	$ 2,591		2,591
Ending balance (in shares) at Sep. 30, 2024	29,777,966	29,777,966
Ending balance at Sep. 30, 2024	$ 9,823	$ 30	$ 535,493		$ (525,700)

Condensed Statements of Stock_2

Condensed Statements of Stockholders’ Equity (unaudited) (Parenthetical) $ in Thousands	3 Months Ended
	Sep. 30, 2024 USD ($)
Statement of Financial Position [Abstract]
Issuance costs	$ 189

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities
Net loss	$ (21,891)	$ (26,756)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	7,679	7,201
Depreciation	159	132
Amortization of debt discount and issuance costs	179	207
Non-cash interest expense	743	775
PIK interest incurred but not paid on term loan	1,389	1,994
Amortization of right-of-use asset	1,159	1,064
(Gain) loss on short-term investments	(315)	580
Inventory write-downs	196	132
Changes in operating assets and liabilities
Accounts receivable	753	(3,798)
Inventory	(1,066)	(179)
Prepaid expenses and other assets	621	1,530
Accounts payable	(102)	(815)
Accrued liabilities	(1,108)	2,623
Deferred revenue	(341)	0
Operating lease liabilities	(1,207)	(1,050)
Net cash used in operating activities	(13,152)	(16,360)
Cash flows from investing activities
Acquisition of property and equipment	(267)	(141)
Proceeds from sale of short-term investments	7,300	19,700
Net cash provided by investing activities	7,033	19,559
Cash flows from financing activities
Proceeds from issuance of common stock under employee plans	1,336	254
Taxes withheld and paid related to net share settlement of equity awards	(789)	(222)
Proceeds from at-the-market offering, net of sales commission	2,932	0
Payment of deferred offering costs	0	(119)
Net cash provided by (used in) financing activities	3,479	(87)
Net (decrease) increase in cash and cash equivalents	(2,640)	3,112
Cash, cash equivalents and restricted cash
Beginning of the period	18,180	6,727
End of the period	15,540	9,839
Reconciliation of cash, cash equivalents and restricted cash to balance sheets:
Cash and cash equivalents	15,418	9,717
Restricted cash	122	122
Cash, cash equivalents and restricted cash in balance sheets	15,540	9,839
Supplemental disclosure of cash flow information:
Cash paid for interest	4,294	3,305
Supplemental disclosures of non-cash investing and financing information:
Deferred offering costs offset against additional paid-in capital	99	0
Net change in accrued liabilities from early exercise of options	$ (1)	$ (1)

The Company

The Company	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The Company NeuroPace, Inc., or the Company, was incorporated in the state of Delaware on November 19, 1997. The Company is a medical device company that has developed the RNS System, the only commercially available brain-responsive neuromodulation system designed for treating drug-resistant focal epilepsy by delivering personalized, real-time treatment at the seizure source. The Company began commercializing its products in the United States in 2014. At-the-Market Equity Offering In November 2022, the Company filed a Registration Statement on Form S-3, or Shelf, with the Securities and Exchange Commission, or the SEC, in relation to the registration of common stock, preferred stock, debt securities, warrants or any combination thereof for up to an aggregate of $150.0 million, of which $50.0 million may be issued and sold pursuant to an at-the-market, or ATM, offering program for sales of the Company’s common stock under a sales agreement, or Sales Agreement, with Leerink Partners LLC, or Leerink (formerly SVB Securities LLC). The Company agreed to pay Leerink up to 3.0% of the gross proceeds of sales of common stock made through the Sales Agreement. The Company’s common stock would be sold at prevailing market prices at the time of the sale and, as a result, prices may vary. In November 2023, the Company sold 933,500 shares of common stock under the Sales Agreement for gross proceeds of $8.1 million, or $7.6 million after deducting sales commissions and offering expenses. During the three months ended September 30, 2024, the Company sold 413,988 shares of common stock under the Sales Agreement for gross proceeds of $3.0 million, or $2.8 million after deducting sales commissions and offering expenses. As of September 30, 2024, the Company has $38.8 million remaining under its ATM program. Liquidity and Capital Resources The Company has incurred operating losses and negative cash flows from operations since its inception and has an accumulated deficit of $525.7 million as of September 30, 2024. For the nine months ended September 30, 2024 and 2023, the Company used $13.2 million and $16.4 million, respectively, of cash in its operating activities. As of September 30, 2024, the Company had cash, cash equivalents and short-term investments of $56.8 million. Historically, the Company has funded its operations principally through the sales of its products, issuance of equity securities and debt financing. The Company’s condensed financial statements have been prepared on the basis of the Company continuing as a going concern for the next 12 months. Management believes that the Company’s cash, cash equivalents and short-term investments will allow the Company to continue its planned operations for at least the next 12 months from the date of the issuance of these unaudited interim condensed financial statements. In connection with the Term Loan described in Note 6, the Company will need to be in compliance with a minimum annual net revenue covenant determined in accordance with generally accepted accounting principles of $70.0 million in each of the years ending December 31, 2024 and December 31, 2025 and maintain a minimum cash and cash equivalents balance of $5.0 million . If the Company cannot generate sufficient revenue in the future, the Company may not be in compliance with the annual net revenue covenant and the lender may call the debt resulting in the Company immediately needing additional capital and resulting in a going concern. The Company’s ability to raise additional capital may be adversely impacted by global economic conditions and disruptions to, and volatility in, the financial markets in the United States and worldwide. If the Company is unable to raise capital when needed, it will need to delay, limit, reduce or terminate planned commercialization or product development activities in order to reduce costs. As of September 30, 2024 , the Company was in compliance with all covenants of the Term Loan.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The unaudited interim condensed financial statements have been prepared in conformity with generally accepted accounting principles in the United States, or GAAP, as defined by the Financial Accounting Standards Board, or the FASB. Unaudited Interim Financial Information The condensed balance sheet as of December 31, 2023 was derived from the Company’s audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed financial statements as of September 30, 2024 and for the three and nine months ended September 30, 2024 and 2023, have been prepared by the Company, pursuant to the rules and regulations of the SEC for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2023 and notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the SEC on March 5, 2024. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s condensed financial position as of September 30, 2024 and condensed results of operations for the three and nine months ended September 30, 2024 and 2023 and condensed cash flows for the nine months ended September 30, 2024 and 2023 have been made. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024. Use of Estimates The preparation of unaudited interim condensed financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. The Company uses significant judgment when making estimates related to the provision for excess and obsolete inventories. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, accounts payable and accrued liabilities, approximate fair value because of the short-term nature of these instruments. The Company has a short-term investment in a fixed income mutual fund, which is classified as equity security and carried at fair value based on quoted market prices. Changes in the fair value of the short-term investment are recorded in income or loss. The Company believes that its borrowings bear interest at the prevailing market rates for instruments with similar characteristics; accordingly, the carrying value of this instrument approximates its fair value. The Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy which establishes three levels of inputs that may be used to measure fair value (see Note 3). Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents, short-term investments and accounts receivable to the extent of the amounts recorded on the balance sheets. The Company’s cash is invested in major financial institutions in the United States. Deposits in these financial institutions may exceed federally insured limits, and the Company is exposed to credit risk on deposits in the event of default of the financial institutions to the extent account balances exceed the amount insured by the Federal Deposit Insurance Corporation. The Company’s cash equivalents are invested in money market funds. The Company’s accounts receivable are due from a variety of health care organizations in the United States. For the three and nine months ended September 30, 2024 and 2023, there were no customers that represented 10% or more of revenue. As of September 30, 2024 and December 31, 2023, no customer represented 10% or more of the Company’s accounts receivable. The Company is subject to certain risks, including that its devices may not be approved or cleared or continue to be approved or cleared for marketing by governmental authorities or be successfully marketed for expanded indications. There can be no assurance that the Company’s products will achieve widespread adoption in the marketplace, nor can there be any assurance that existing devices or any future devices can be developed or manufactured at an acceptable cost and speed and with appropriate performance characteristics. The Company is also subject to risks common to companies in the medical device industry, including, but not limited to, new technological innovations, dependence on healthcare providers to prescribe initial implants and replacements, dependence upon third-party payors to provide adequate coverage and reimbursement, dependence on key personnel, single-source suppliers and vendors in connection with the manufacture of its products, concentration of comprehensive epilepsy centers, or CECs, and epileptologists, obtaining, maintaining, protecting, enforcing, and defending intellectual property rights and proprietary technology, product liability claims, legal proceedings, and compliance with government regulations. The Company’s medical devices require approvals or clearances from the U.S. Food and Drug Administration, or the FDA, or international regulatory agencies. In addition, in order to continue the Company’s operations, compliance with various federal and state laws is required. If approvals or clearances were withdrawn by the FDA for the Company’s current products or if such approvals or clearances were denied or delayed for future products, product updates, or expanded indications for use, it would have a material adverse impact on the Company. Accounts Receivable Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company makes estimates on the collectability of customer accounts based primarily on analysis of historical trends and experience, the age of the receivable and changes in customers’ financial condition. The Company uses its judgment, based on the best available facts and circumstances, and records an allowance against amounts due to reduce the receivable to the amount that is expected to be collected. The Company determined that no allowance was required as of September 30, 2024 and December 31, 2023. To date, the Company has not experienced any material credit-related losses. Remaining Performance Obligation and Contract Liabilities The Company’s contract liabilities consist of deferred revenue of $0.7 million and $1.1 million as of September 30, 2024 and December 31, 2023, respectively. Revenue recognized during the three and nine months ended September 30, 2024 that was included in the deferred revenue balance at the beginning of the year was immaterial. No such revenue was recognized during the three and nine months ended September 30, 2023. As of September 30, 2024, the aggregate amount of the transaction price allocated to the remaining performance obligations that are unsatisfied or partially unsatisfied was $1.9 million, which the Company expects to recognize as revenue by December 2025 pursuant to customer contract terms. Government Programs In May 2021, the Company was awarded a grant by the National Institutes of Health, or NIH, to support research of thalamocortical responsive neurostimulation for the treatment of Lennox-Gastaut Syndrome, a type of epilepsy. The award was issued for a five-year period and has a total budget of over $9.3 million, which includes approximately $5.5 million in funding for subawards to third party academic epilepsy centers that are collaborating on the study and are subinvestigators on the study funded by NIH. The subawardees are determined by NIH. The Company’s responsibility for the subawards is to submit the funding requests on behalf of the subawardees. The funding of subawards does not have any impact on the Company’s condensed financial statements. Initially funding was approved for the first year beginning June 1, 2021 and provides for reimbursement of qualified direct and indirect expenses in the amount of $0.8 million, including $0.4 million for subawards. Approvals of funds for years two through five are subject to the completion of certain milestones. On July 30, 2022, the Company received funding approval for year two in the amount of $2.6 million, which includes $1.6 million for subawards. On May 25, 2023, the Company received funding approval for year three in the amount of $3.0 million, which includes $1.5 million for subawards. On July 22, 2024, the Company received funding approval for year four in the amount of $1.7 million, which includes $1.0 million for subawards. For funds received under the NIH funding agreement, the Company recognizes a reduction in research and development expenses in an amount equal to the qualifying expenses incurred in each period up to the amount awarded by the NIH. The Company received $0.4 million and $0.5 million in funding during the three months ended September 30, 2024 and 2023, respectively. The Company received $1.4 million and $1.0 million in funding during the nine months ended September 30, 2024 and 2023, respectively. Through September 30, 2024, $3.5 million of qualifying expenses have been incurred and funded by the NIH related to the first to fourth year of funding. Qualifying expenses incurred by the Company in advance of funding by the NIH are recorded within prepaid expenses and other current assets on the balance sheets. As of September 30, 2024, the Company recorded prepaid expenses and other current assets of $0.3 million related to the fourth year of funding. Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options, common stock subject to repurchase related to early exercise of stock options, and restricted stock units are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities. The Company considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities, because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of the shares issued upon early exercise of stock options subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. Recent Accounting Pronouncements Recent Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . The amendments in this ASU require disclosures, on an annual and interim basis, of significant segment expenses that are regularly provided to the chief operating decision maker, or CODM, as well as the aggregate amount of other segment items included in the reported measure of segment profit or loss. This ASU requires that a public entity disclose the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. Public entities will be required to provide all annual disclosures currently required by Topic 280 in interim periods, and entities with a single reportable segment are required to provide all the disclosures required by the amendments in this ASU and existing segment disclosures in Topic 280. This ASU is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. This ASU is applicable to the Company beginning with its Annual Report on Form 10-K for the fiscal year ending December 31, 2024. The Company is currently evaluating the impact this standard will have on the disclosures included in the notes to the financial statements. In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures . This ASU requires greater disaggregation of information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid. This ASU applies to all entities subject to income taxes and is intended to help investors better understand an entity’s exposure to potential changes in jurisdictional tax legislation and assess income tax information that affects cash flow forecasts and capital allocation decisions. This ASU is effective for annual periods beginning after December 15, 2024, with early adoption permitted, and should be applied on a prospective basis although retrospective application is permitted. The Company is currently evaluating the impact this standard will have on the disclosures included in the notes to the financial statements. In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40) . This ASU is intended to provide more detailed information about specified categories of expenses (including employee compensation, depreciation, and amortization) included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. This ASU may be applied either prospectively to financial statements issued for reporting periods after its effective date or retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this standard will have on its financial statement disclosures. The Company continues to monitor new accounting pronouncements issued by the FASB and does not believe any accounting pronouncements issued through the date of this report will have a material impact on the Company’s financial statements.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 2 Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company utilizes the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The following table summarizes the Company’s financial assets (cash equivalents and marketable securities) at fair value as of September 30, 2024 (in thousands): Fair Value as of September 30, 2024 Basis for Fair Value Measurements (Level 1) (Level 2) (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 14,968 $ 14,968 $ — $ — Fixed income mutual fund, included in short-term investments 41,412 41,412 — — Total $ 56,380 $ 56,380 $ — $ — The following table summarizes the Company’s financial assets (cash equivalents and marketable securities) at fair value as of December 31, 2023 (in thousands): Fair Value as of December 31, 2023 Basis for Fair Value Measurements (Level 1) (Level 2) (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 16,125 $ 16,125 $ — $ — Fixed income mutual fund, included in short-term investments 48,396 48,396 — — Total $ 64,521 $ 64,521 $ — $ — There were no liabilities measured at fair value on a recurring and non-recurring basis as of September 30, 2024 and December 31, 2023. The money market funds are highly liquid and primarily invest in short-term fixed income securities issued by the U.S. government and U.S. government agencies. The Company’s available-for-sale investment comprises a short-term investment in a fixed income mutual fund, which primarily invests in debt securities issued by the U.S. government and U.S. government agencies and corporate bonds and notes. Interest income from short-term investment is recorded in interest income. During the three months ended September 30, 2024 and 2023, the Company recognized $0.2 million and $0.1 million in unrealized gains from its short-term investment, respectively. During the nine months ended September 30, 2024 and 2023, the Company recognized $0.3 million and $0.7 million in unrealized gains from its short-term investment, respectively. As of September 30, 2023, the Company’s short-term investment had a cumulative unrealized net loss of $0.4 million, which included an adjustment of $1.1 million unrealized loss recorded in other income (expense), net in the nine months ended September 30, 2023. The adjustment was not material to any previously issued financial statements. The Company’s short-term investment had a cumulative unrealized net gain of $0.2 million as of September 30, 2024, and cumulative unrealized net loss of $0.1 million as of December 31, 2023.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Inventory Inventories consist of the following (in thousands): September 30, December 31, 2024 2023 Raw materials $ 4,260 $ 4,090 Work-in-process 1,492 627 Finished goods 6,332 6,497 Total $ 12,084 $ 11,214 Property and Equipment, net Property and equipment, net consists of the following (in thousands): September 30, December 31, 2024 2023 Machinery, equipment, furniture and fixtures $ 4,609 $ 4,522 Computer equipment and software 1,932 1,822 Leasehold improvements 2,426 2,426 8,967 8,770 Less: Accumulated depreciation (7,926) (7,767) Property and equipment, net $ 1,041 $ 1,003 Depreciation expense for the three months ended September 30, 2024 and 2023 was $0.1 million and less than $0.1 million, respectively. Depreciation expense for the nine months ended September 30, 2024 and 2023 was $0.2 million and $0.1 million, respectively. Accrued Liabilities Accrued liabilities consist of the following (in thousands): September 30, December 31, 2024 2023 Payroll and related expenses $ 7,635 $ 9,655 Inventory purchases 1,478 588 Professional fees 120 30 Other 839 907 Total accrued liabilities $ 10,072 $ 11,180

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Facility Lease In August 2011, the Company entered into a non-cancelable operating lease for combined office and manufacturing facilities in Mountain View, California. The lease was scheduled to expire in April 2019 and was amended in May 2018 to extend it through June 2024. In August 2022, the Company amended the lease to extend it through June 2030. The second amendment contained a rent-free period from September 2022 through December 2022. The Company has an option to extend the lease for a period of five years, commencing on July 1, 2030 and expiring on June 30, 2035. In conjunction with the original lease agreement, the Company obtained a letter of credit for $0.9 million in lieu of a security deposit. In May 2019, the letter of credit was amended and reduced to $0.7 million. In June 2021, the letter of credit was amended and further reduced to $0.2 million. The terms of the facility lease provide for rental payments on a graduated scale; however, rent expense is recognized on a straight-line basis over the lease term. Rental payments range from $2.8 million to $3.3 million per year over the extended term of the lease. The maturities of operating lease liabilities as of September 30, 2024 are as follows (in thousands): September 30, 2024 (remaining three months) $ 714 2025 2,942 2026 3,031 2027 3,122 2028 3,215 Thereafter 5,017 Total undiscounted lease payments 18,041 Less: imputed interest 3,808 Total operating lease liability 14,233 Less: current portion 1,800 Operating lease liability, net of current portion $ 12,433 Operating lease cost was $0.7 million and $0.7 million for the three months ended September 30, 2024 and 2023, respectively. Operating lease cost was $2.1 million and $2.1 million for the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024, the remaining term for the operating lease in Mountain View, California was 5.8 years, and the discount rate used to measure the lease liability for such operating lease upon recognition was 8.5%. During the nine months ended September 30, 2024 and 2023, cash paid for amounts included in operating lease liabilities of $2.1 million and $2.1 million, respectively, was included in cash flows from operating activities on the condensed statements of cash flows. Distribution Agreement In August 2022, the Company entered into an exclusive distribution agreement, or the Distribution Agreement, with DIXI Medical USA Corp, or DIXI Medical, pursuant to which the Company became the exclusive U.S. distributor of DIXI Medical’s stereo electroencephalography product line. The Distribution Agreement has an initial term of three years, which expires September 30, 2025, and which may be automatically renewed for additional one-year terms, unless either party provides written notice to the other party of its intention to not renew at least 180 days prior to the expiration of the then-current term. To maintain the distribution rights, the Company is committed to purchase a minimum of $2.4 million of DIXI Medical’s products during the twelve months beginning October 2022, and to increase the purchase minimum by 10% for each of the two subsequent years. The Company met the purchase commitment for the first two years. Indemnifications In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and may provide for indemnification of the counterparty. The Company’s exposure under these agreements is unknown because it involves claims that may be made against it in the future but have not yet been made. The Company may, from time to time, be subject to claims or be required to defend actions related to its indemnification obligations. The Company indemnifies each of its directors and officers for certain events or occurrences, subject to certain limits, while the director or officer is or was serving at the Company’s request in such capacity, as permitted under Delaware law and in accordance with its certificate of incorporation and bylaws. The term of the indemnification period lasts as long as the director or officer may be subject to any proceeding arising out of acts or omissions of such individual in such capacity. The maximum amount of potential future indemnification is unlimited. The Company believes that the fair value of these indemnification obligations is minimal. Accordingly, the Company has not recognized any liabilities relating to these obligations as of September 30, 2024 and December 31, 2023. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. The Company determined that no accrual related to contingencies was required as of September 30, 2024 and December 31, 2023. Legal Proceedings The Company is not involved in any pending legal proceedings that it believes could have a material adverse effect on its business, results of operations, financial condition, or cash flows. From time to time, the Company may pursue litigation to assert its legal rights and such litigation may be costly and divert the efforts and attention of its management and technical personnel which could adversely affect its business. The Company regularly evaluates current information to determine whether any accruals should be adjusted and whether new accruals are required. Such accruals, if any, reflect the estimable and probable costs that the Company may incur from the outcomes of its legal proceedings. Legal costs are expensed as incurred. There were no contingent liabilities requiring accrual as of September 30, 2024 and December 31, 2023.

Debt

Debt	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Debt	Debt Term Loan In September 2020, the Company entered into a Term Loan Agreement with CRG Partners IV L.P. and its affiliates for total borrowings of up to $60.0 million, or the Term Loan, and borrowed $50.0 million. The remaining $10.0 million of the Term Loan was available to the Company for borrowing until March 31, 2022 if the Company achieved a revenue-based milestone in 2021. The revenue-based milestone was not achieved, and the remaining $10.0 million of the Term Loan expired without being drawn. The Term Loan initially bore interest at a rate of 12.5% per year. In February 2023, the Term Loan was amended which increased the annual interest rate from 12.5% to 13.5% effective March 1, 2023. The amendment was accounted for as a debt modification in accordance with Accounting Standards Codification - Debt (Topic 470) and the Term Loan’s effective interest rate increased from 15.7% to 16.8%. Payments under the Term Loan are made quarterly with payment dates fixed at the end of each calendar quarter. Through December 2020, the Company had the option to pay the entire interest paid-in-kind, or PIK, by increasing the principal of the Term Loan. From January 2021 through December 2022, the Company had the option to pay interest as follows: 7.5% per annum paid in cash and 5.0% per annum PIK by increasing the principal of the Term Loan. From January 2023 through June 2025, the Company had the option to pay interest as follows: 8.5% per annum paid in cash and 5.0% per annum PIK by increasing the principal of the Term Loan. For each payment date from April 2022 through June 2024, the Company elected the PIK option, increasing the principal of the Term Loan by $6.0 million. The Term Loan was interest-only through September 2023, which could be extended through September 2025 at the Company’s option if the Company completed its initial public offering, or IPO, on or prior to September 30, 2023. In connection with closing the IPO in April 2021, the Company extended the interest-only period to September 30, 2025. Following the interest-only period, principal payment was to be due in one installment on September 30, 2025. In May 2024, the Term Loan was amended to extend the final maturity by one year to September 30, 2026 and eliminate the PIK interest option after June 30, 2024. The amendment was accounted for as a troubled debt restructuring in accordance with Accounting Standards Codification - Debt (Topic 470) and no gain or loss was recognized. The Term Loan includes a fee upon repayment of the loan equal to 10% of the aggregate principal amount being prepaid or repaid, or the backend fee. As of September 30, 2024, the Term Loan had an annual effective interest rate of 15.5% per year. The Term Loan is collateralized by substantially all of the Company’s assets. The Term Loan Agreement contains customary representations and warranties, covenants, events of default and termination provisions. The financial covenants require that the Company achieve minimum annual revenue thresholds commencing in 2021 and maintain a minimum balance of cash and cash equivalents (see Note 1). In February 2023, the Term Loan was amended to reduce the minimum annual net revenue covenant to $45.0 million for the year ended December 31, 2023. The Company paid $1.0 million in fees to the lender and third parties which is reflected as a discount on the loan and is being accreted over the life of the loan using the effective interest method. Also, the Company issued warrants to the lender for a total of 346,823 shares of Series B’ redeemable convertible preferred stock. The warrants had a fair value of $0.6 million as of the issuance date, which was accounted for as debt issuance costs. During the three months ended September 30, 2024 and 2023, the Company recorded interest expense related to debt discount and debt issuance costs of the Term Loan of less than $0.1 million and $0.1 million, respectively. During the nine months ended September 30, 2024 and 2023, the Company recorded interest expense related to debt discount and debt issuance costs of the Term Loan of $0.2 million and $0.2 million, respectively. Interest expense on the Term Loan was $2.2 million and $2.2 million during the three months ended September 30, 2024 and 2023, respectively. Interest expense on the Term Loan was $6.6 million and $6.3 million during the nine months ended September 30, 2024 and 2023, respectively. As of September 30, 2024, future minimum payments for the Term Loan are as follows (in thousands): Term Loan 2024 (remaining three months) $ 1,932 2025 7,666 2026 67,341 Total 76,939 Less: Unamortized debt discount and issuance cost (441) Less: Unaccreted backend fee (1,900) Less: Interest (15,332) Term Loan $ 59,266

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Common Stock	Common Stock The Company’s Amended and Restated Certificate of Incorporation authorizes the Company to issue 200,000,000 shares of $0.001 par value common stock. The holders of common stock are entitled to receive dividends whenever funds and assets are legally available and when declared by the Board of Directors. As of September 30, 2024 and December 31, 2023, no dividends had been declared. As of September 30, 2024 and December 31, 2023, the Company had reserved common stock for future issuance pursuant to its equity plans as follows: September 30, December 31, 2024 2023 Shares available for future grant under the 2021 Equity Incentive Plan 2,215,236 1,314,502 Outstanding options under the 2021 Equity Incentive Plan 2,033,992 2,208,341 Outstanding options under the 2023 Inducement Plan 380,424 380,424 Outstanding restricted stock units under the 2021 Equity Incentive Plan 1,648,539 2,430,803 Common stock available for Employee Stock Purchase Plan 583,289 399,798 Total 6,861,480 6,733,868

Stock-Based Incentive Compensat

Stock-Based Incentive Compensation Plans	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Incentive Compensation Plans	Stock-Based Incentive Compensation Plans A summary of shares available for grant under the Company’s 2021 Equity Incentive Plan, or the 2021 Plan, is as follows: Shares Available for Grant Shares available for grant as of January 1, 2024 1,314,502 Authorized 1,391,173 Granted/Awarded (1,073,758) Cancelled 527,313 Withheld for taxes 56,006 Shares available for grant as of September 30, 2024 2,215,236 A summary of stock option activity for the nine months ended September 30, 2024 is set forth below: Options Outstanding Number of Shares Weighted-Average Exercise Price Weighted Average Remaining Contractual Term (in Years) Balances as of January 1, 2024 2,588,765 $ 4.51 7.17 Granted 487,654 $ 12.33 Exercised (519,314) $ 1.56 Cancelled (142,689) $ 14.67 Balances at September 30, 2024 2,414,416 $ 6.12 7.37 Vested and exercisable at September 30, 2024 1,548,358 $ 4.67 6.50 Vested and expected to vest at September 30, 2024 2,414,416 $ 6.12 7.37 Early Exercise of Stock Options Certain of the Company’s outstanding options are early exercisable pursuant to their terms. The shares of common stock issued from the early exercise of unvested stock options are restricted and continue to vest over the original implied service period. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The shares purchased by the employees and non-employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for exercised and unvested shares related to stock options granted is recorded as a liability for the early exercise of stock options in accrued liabilities on the accompanying balance sheet and will be transferred into common stock and additional paid-in capital as the shares vest. As of September 30, 2024 and December 31, 2023, there were 0 and 30,211 shares of common stock, respectively, issued pursuant to early exercised options and subject to repurchase. Employee Stock Purchase Plan In April 2021, the Company adopted the 2021 Employee Stock Purchase Plan, or ESPP. The Company allows eligible employees to purchase shares of the Company's common stock through payroll deductions at a price equal to 85% of the lesser of the fair market value of the stock as of the first date or the ending date of each offering period, which is typically six months. There were 580,000 shares of common stock initially reserved for issuance under the ESPP. In January 2024, the number of shares of common stock available for issuance under the ESPP was increased by 278,234 shares as a result of the automatic increase provision in the ESPP. As of September 30, 2024, 583,289 shares under the ESPP remain available for purchase. The Company issued 94,743 and 164,710 shares under the ESPP during the nine months ended September 30, 2024 and 2023, respectively. The offering period and purchase period is determined by the board of directors. A new offering period of six months began June 7, 2024 and will end December 6, 2024. Restricted Stock Units Activity with respect to restricted stock units was as follows: Number of Shares Underlying Outstanding Restricted Stock Units Weighted Average Grant Date Fair Value Unvested, January 1, 2024 2,430,803 $ 6.52 Granted 586,104 $ 13.45 Vested (983,744) $ 6.45 Cancelled (384,624) $ 7.61 Unvested, September 30, 2024 1,648,539 $ 8.77 Stock-Based Compensation The Company recognized stock-based compensation as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Cost of goods sold $ 180 $ 155 $ 539 $ 449 Research and development 816 751 2,421 1,984 Selling, general and administrative 1,595 1,515 4,719 4,768 Total stock-based compensation $ 2,591 $ 2,421 $ 7,679 $ 7,201 The above stock-based compensation expense related to the following equity-based awards (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Stock options and restricted stock units $ 2,462 $ 2,333 $ 7,284 $ 7,010 ESPP 129 88 395 191 Total stock-based compensation $ 2,591 $ 2,421 $ 7,679 $ 7,201 As of September 30, 2024, the total unrecognized stock-based compensation expense related to unvested stock options and restricted stock units was $16.9 million, which will be amortized on a straight-line basis over a weighted average remaining period of 2.2 years. As of September 30, 2024, the Company had unrecognized stock-based compensation expense relating to the ESPP awards of $0.1 million, which is expected to be recognized over a weighted-average period of 0.2 years.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company did not record a federal or state income tax provision or benefit for the three and nine months ended September 30, 2024 and 2023 as it has incurred net losses since inception. In addition, the net deferred tax assets generated from net operating losses are fully offset by a valuation allowance as the Company believes it is not more likely than not that the benefit will be realized. The Company accounts for the uncertainty in income taxes by utilizing a comprehensive model for the recognition, measurement, presentation and disclosure in financial statements of any uncertain tax positions that have been taken or are expected to be taken on an income tax return. There has been no change in the estimated uncertain tax benefits recorded as of December 31, 2023.

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except for share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss attributable to common stockholders $ (5,452) $ (7,257) $ (21,891) $ (26,756) Denominator: Weighted-average common stock outstanding used to compute basic and diluted net loss per share 29,444,625 26,017,329 28,863,120 25,532,415 Net loss per share attributable to common stockholders, basic and diluted $ (0.19) $ (0.28) $ (0.76) $ (1.05) The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted average shares outstanding because such securities have an antidilutive impact due to the Company’s net loss, in common stock equivalent shares: As of September 30, 2024 2023 Options to purchase common stock 2,414,416 2,984,317 Unvested restricted stock units 1,648,539 2,516,101 Shares committed under ESPP 105,837 122,451 Unvested early exercised common stock options — 41,907 Total Shares 4,168,792 5,664,776

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (5,452)	$ (7,514)	$ (8,925)	$ (7,257)	$ (9,124)	$ (10,375)	$ (21,891)	$ (26,756)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	9 Months Ended
	Sep. 30, 2024 shares	Sep. 30, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		During the quarter ended September 30, 2024, our directors and officers (as defined in Rule 16a-1(f) under the Exchange Act) adopted or terminated the contracts, instructions, or written plans for the purchase or sale of our securities set forth in the table below: Name and Position Action Adoption/Termination Date Type of Trading Arrangement: Rule 10b5-1 (1) Total Shares of Common Stock to be Sold Expiration Date Martha Morrell, Chief Medical Officer Adoption September 17, 2024 X 92,232 (2) June 30, 2025 _________________ (1) Contract, instruction or written plan intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act. (2) Including the exercise and sale of up to 92,232 shares of the Company’s common stock subject to stock options.
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Martha Morrell [Member]
Trading Arrangements, by Individual
Name	Martha Morrell
Title	Chief Medical Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	September 17, 2024
Expiration Date	June 30, 2025
Arrangement Duration	286 days
Aggregate Available	92,232	92,232

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation and Unaudited Interim Financial Information	Basis of Presentation The unaudited interim condensed financial statements have been prepared in conformity with generally accepted accounting principles in the United States, or GAAP, as defined by the Financial Accounting Standards Board, or the FASB. Unaudited Interim Financial Information The condensed balance sheet as of December 31, 2023 was derived from the Company’s audited financial statements, but does not include all disclosures required by GAAP. The accompanying unaudited condensed financial statements as of September 30, 2024 and for the three and nine months ended September 30, 2024 and 2023, have been prepared by the Company, pursuant to the rules and regulations of the SEC for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. Accordingly, these financial statements should be read in conjunction with the audited financial statements as of and for the year ended December 31, 2023 and notes thereto, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the SEC on March 5, 2024. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s condensed financial position as of September 30, 2024 and condensed results of operations for the three and nine months ended September 30, 2024 and 2023 and condensed cash flows for the nine months ended September 30, 2024 and 2023 have been made. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2024.
Use of Estimates	Use of Estimates The preparation of unaudited interim condensed financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts and disclosures reported in the financial statements. The Company uses significant judgment when making estimates related to the provision for excess and obsolete inventories. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Fair Value of Financial Instruments and Fair Value Measurements	Fair Value of Financial Instruments The Company measures certain financial assets and liabilities at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 2 Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company utilizes the market approach to measure fair value for its financial assets and liabilities. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities.
Concentration of Credit Risk, and Other Risks and Uncertainties	Concentration of Credit Risk, and Other Risks and Uncertainties Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents, short-term investments and accounts receivable to the extent of the amounts recorded on the balance sheets. The Company’s cash is invested in major financial institutions in the United States. Deposits in these financial institutions may exceed federally insured limits, and the Company is exposed to credit risk on deposits in the event of default of the financial institutions to the extent account balances exceed the amount insured by the Federal Deposit Insurance Corporation. The Company’s cash equivalents are invested in money market funds. The Company’s accounts receivable are due from a variety of health care organizations in the United States. For the three and nine months ended September 30, 2024 and 2023, there were no customers that represented 10% or more of revenue. As of September 30, 2024 and December 31, 2023, no customer represented 10% or more of the Company’s accounts receivable. The Company is subject to certain risks, including that its devices may not be approved or cleared or continue to be approved or cleared for marketing by governmental authorities or be successfully marketed for expanded indications. There can be no assurance that the Company’s products will achieve widespread adoption in the marketplace, nor can there be any assurance that existing devices or any future devices can be developed or manufactured at an acceptable cost and speed and with appropriate performance characteristics. The Company is also subject to risks common to companies in the medical device industry, including, but not limited to, new technological innovations, dependence on healthcare providers to prescribe initial implants and replacements, dependence upon third-party payors to provide adequate coverage and reimbursement, dependence on key personnel, single-source suppliers and vendors in connection with the manufacture of its products, concentration of comprehensive epilepsy centers, or CECs, and epileptologists, obtaining, maintaining, protecting, enforcing, and defending intellectual property rights and proprietary technology, product liability claims, legal proceedings, and compliance with government regulations. The Company’s medical devices require approvals or clearances from the U.S. Food and Drug Administration, or the FDA, or international regulatory agencies. In addition, in order to continue the Company’s operations, compliance with various federal and state laws is required. If approvals or clearances were withdrawn by the FDA for the Company’s current products or if such approvals or clearances were denied or delayed for future products, product updates, or expanded indications for use, it would have a material adverse impact on the Company.
Accounts Receivable	Accounts Receivable Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company makes estimates on the collectability of customer accounts based primarily on analysis of historical trends and experience, the age of the receivable and changes in customers’ financial condition. The Company uses its judgment, based on the best available facts and circumstances, and records an allowance against amounts due to reduce the receivable to the amount that is expected to be collected. The Company determined that no allowance was required as of September 30, 2024 and December 31, 2023. To date, the Company has not experienced any material credit-related losses.
Government Programs	Government Programs In May 2021, the Company was awarded a grant by the National Institutes of Health, or NIH, to support research of thalamocortical responsive neurostimulation for the treatment of Lennox-Gastaut Syndrome, a type of epilepsy. The award was issued for a five-year period and has a total budget of over $9.3 million, which includes approximately $5.5 million in funding for subawards to third party academic epilepsy centers that are collaborating on the study and are subinvestigators on the study funded by NIH. The subawardees are determined by NIH. The Company’s responsibility for the subawards is to submit the funding requests on behalf of the subawardees. The funding of subawards does not have any impact on the Company’s condensed financial statements. Initially funding was approved for the first year beginning June 1, 2021 and provides for reimbursement of qualified direct and indirect expenses in the amount of $0.8 million, including $0.4 million for subawards. Approvals of funds for years two through five are subject to the completion of certain milestones. On July 30, 2022, the Company received funding approval for year two in the amount of $2.6 million, which includes $1.6 million for subawards. On May 25, 2023, the Company received funding approval for year three in the amount of $3.0 million, which includes $1.5 million for subawards. On July 22, 2024, the Company received funding approval for year four in the amount of $1.7 million, which includes $1.0 million for subawards. For funds received under the NIH funding agreement, the Company recognizes a reduction in research and development expenses in an amount equal to the qualifying expenses incurred in each period up to the amount awarded by the NIH. The Company received $0.4 million and $0.5 million in funding during the three months ended September 30, 2024 and 2023, respectively. The Company received $1.4 million and $1.0 million in funding during the nine months ended September 30, 2024 and 2023, respectively. Through September 30, 2024, $3.5 million of qualifying expenses have been incurred and funded by the NIH related to the first to fourth year of funding. Qualifying expenses incurred by the Company in advance of funding by the NIH are recorded within prepaid expenses and other current assets on the balance sheets. As of September 30, 2024, the Company recorded prepaid expenses and other current assets of $0.3 million related to the fourth year of funding.
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options, common stock subject to repurchase related to early exercise of stock options, and restricted stock units are considered to be potentially dilutive securities. Basic and diluted net loss attributable to common stockholders per share is presented in conformity with the two-class method required for participating securities. The Company considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities, because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of the shares issued upon early exercise of stock options subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recent Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures . The amendments in this ASU require disclosures, on an annual and interim basis, of significant segment expenses that are regularly provided to the chief operating decision maker, or CODM, as well as the aggregate amount of other segment items included in the reported measure of segment profit or loss. This ASU requires that a public entity disclose the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. Public entities will be required to provide all annual disclosures currently required by Topic 280 in interim periods, and entities with a single reportable segment are required to provide all the disclosures required by the amendments in this ASU and existing segment disclosures in Topic 280. This ASU is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The amendments in this ASU should be applied retrospectively to all prior periods presented in the financial statements. This ASU is applicable to the Company beginning with its Annual Report on Form 10-K for the fiscal year ending December 31, 2024. The Company is currently evaluating the impact this standard will have on the disclosures included in the notes to the financial statements. In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures . This ASU requires greater disaggregation of information about a reporting entity's effective tax rate reconciliation as well as information on income taxes paid. This ASU applies to all entities subject to income taxes and is intended to help investors better understand an entity’s exposure to potential changes in jurisdictional tax legislation and assess income tax information that affects cash flow forecasts and capital allocation decisions. This ASU is effective for annual periods beginning after December 15, 2024, with early adoption permitted, and should be applied on a prospective basis although retrospective application is permitted. The Company is currently evaluating the impact this standard will have on the disclosures included in the notes to the financial statements. In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40) . This ASU is intended to provide more detailed information about specified categories of expenses (including employee compensation, depreciation, and amortization) included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. This ASU may be applied either prospectively to financial statements issued for reporting periods after its effective date or retrospectively to all prior periods presented in the financial statements. The Company is currently assessing the impact this standard will have on its financial statement disclosures. The Company continues to monitor new accounting pronouncements issued by the FASB and does not believe any accounting pronouncements issued through the date of this report will have a material impact on the Company’s financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities, Measured at Fair Value	The following table summarizes the Company’s financial assets (cash equivalents and marketable securities) at fair value as of September 30, 2024 (in thousands): Fair Value as of September 30, 2024 Basis for Fair Value Measurements (Level 1) (Level 2) (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 14,968 $ 14,968 $ — $ — Fixed income mutual fund, included in short-term investments 41,412 41,412 — — Total $ 56,380 $ 56,380 $ — $ — The following table summarizes the Company’s financial assets (cash equivalents and marketable securities) at fair value as of December 31, 2023 (in thousands): Fair Value as of December 31, 2023 Basis for Fair Value Measurements (Level 1) (Level 2) (Level 3) Assets: Money market funds, included in cash and cash equivalents $ 16,125 $ 16,125 $ — $ — Fixed income mutual fund, included in short-term investments 48,396 48,396 — — Total $ 64,521 $ 64,521 $ — $ —

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Inventory, Current	Inventories consist of the following (in thousands): September 30, December 31, 2024 2023 Raw materials $ 4,260 $ 4,090 Work-in-process 1,492 627 Finished goods 6,332 6,497 Total $ 12,084 $ 11,214
Schedule of Property, Plant and Equipment	Property and equipment, net consists of the following (in thousands): September 30, December 31, 2024 2023 Machinery, equipment, furniture and fixtures $ 4,609 $ 4,522 Computer equipment and software 1,932 1,822 Leasehold improvements 2,426 2,426 8,967 8,770 Less: Accumulated depreciation (7,926) (7,767) Property and equipment, net $ 1,041 $ 1,003
Schedule of Accrued Liabilities	Accrued liabilities consist of the following (in thousands): September 30, December 31, 2024 2023 Payroll and related expenses $ 7,635 $ 9,655 Inventory purchases 1,478 588 Professional fees 120 30 Other 839 907 Total accrued liabilities $ 10,072 $ 11,180

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Maturities of Operating Lease Liabilities	The maturities of operating lease liabilities as of September 30, 2024 are as follows (in thousands): September 30, 2024 (remaining three months) $ 714 2025 2,942 2026 3,031 2027 3,122 2028 3,215 Thereafter 5,017 Total undiscounted lease payments 18,041 Less: imputed interest 3,808 Total operating lease liability 14,233 Less: current portion 1,800 Operating lease liability, net of current portion $ 12,433

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt	As of September 30, 2024, future minimum payments for the Term Loan are as follows (in thousands): Term Loan 2024 (remaining three months) $ 1,932 2025 7,666 2026 67,341 Total 76,939 Less: Unamortized debt discount and issuance cost (441) Less: Unaccreted backend fee (1,900) Less: Interest (15,332) Term Loan $ 59,266

Common Stock (Tables)

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Schedule of Stock by Class	As of September 30, 2024 and December 31, 2023, the Company had reserved common stock for future issuance pursuant to its equity plans as follows: September 30, December 31, 2024 2023 Shares available for future grant under the 2021 Equity Incentive Plan 2,215,236 1,314,502 Outstanding options under the 2021 Equity Incentive Plan 2,033,992 2,208,341 Outstanding options under the 2023 Inducement Plan 380,424 380,424 Outstanding restricted stock units under the 2021 Equity Incentive Plan 1,648,539 2,430,803 Common stock available for Employee Stock Purchase Plan 583,289 399,798 Total 6,861,480 6,733,868

Stock-Based Incentive Compens_2

Stock-Based Incentive Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Available for Grant	A summary of shares available for grant under the Company’s 2021 Equity Incentive Plan, or the 2021 Plan, is as follows: Shares Available for Grant Shares available for grant as of January 1, 2024 1,314,502 Authorized 1,391,173 Granted/Awarded (1,073,758) Cancelled 527,313 Withheld for taxes 56,006 Shares available for grant as of September 30, 2024 2,215,236
Schedule of Stock Option Activity	A summary of stock option activity for the nine months ended September 30, 2024 is set forth below: Options Outstanding Number of Shares Weighted-Average Exercise Price Weighted Average Remaining Contractual Term (in Years) Balances as of January 1, 2024 2,588,765 $ 4.51 7.17 Granted 487,654 $ 12.33 Exercised (519,314) $ 1.56 Cancelled (142,689) $ 14.67 Balances at September 30, 2024 2,414,416 $ 6.12 7.37 Vested and exercisable at September 30, 2024 1,548,358 $ 4.67 6.50 Vested and expected to vest at September 30, 2024 2,414,416 $ 6.12 7.37
Schedule of Restricted Stock Units	Activity with respect to restricted stock units was as follows: Number of Shares Underlying Outstanding Restricted Stock Units Weighted Average Grant Date Fair Value Unvested, January 1, 2024 2,430,803 $ 6.52 Granted 586,104 $ 13.45 Vested (983,744) $ 6.45 Cancelled (384,624) $ 7.61 Unvested, September 30, 2024 1,648,539 $ 8.77
Schedule of Share-based Payment Arrangement, Expensed and Capitalized, Amount	The Company recognized stock-based compensation as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Cost of goods sold $ 180 $ 155 $ 539 $ 449 Research and development 816 751 2,421 1,984 Selling, general and administrative 1,595 1,515 4,719 4,768 Total stock-based compensation $ 2,591 $ 2,421 $ 7,679 $ 7,201 The above stock-based compensation expense related to the following equity-based awards (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Stock options and restricted stock units $ 2,462 $ 2,333 $ 7,284 $ 7,010 ESPP 129 88 395 191 Total stock-based compensation $ 2,591 $ 2,421 $ 7,679 $ 7,201

Net Loss per Share Attributab_2

Net Loss per Share Attributable to Common Stockholders (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except for share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net loss attributable to common stockholders $ (5,452) $ (7,257) $ (21,891) $ (26,756) Denominator: Weighted-average common stock outstanding used to compute basic and diluted net loss per share 29,444,625 26,017,329 28,863,120 25,532,415 Net loss per share attributable to common stockholders, basic and diluted $ (0.19) $ (0.28) $ (0.76) $ (1.05)
Schedule of Potentially Dilutive Securities Outstanding	The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted average shares outstanding because such securities have an antidilutive impact due to the Company’s net loss, in common stock equivalent shares: As of September 30, 2024 2023 Options to purchase common stock 2,414,416 2,984,317 Unvested restricted stock units 1,648,539 2,516,101 Shares committed under ESPP 105,837 122,451 Unvested early exercised common stock options — 41,907 Total Shares 4,168,792 5,664,776

The Company (Details)

The Company (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended	9 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Aggregate net proceeds				$ 2,932	$ 0
Accumulated deficit			$ 525,700	525,700		$ 503,809
Net cash used in operating activities				13,152	$ 16,360
Cash, cash equivalents, and short-term investments			56,800	56,800
Minimum annual net revenue				70,000
Minimum cash and cash equivalents required after completion of IPO			$ 5,000	5,000
At-the-Market Equity Offering
Finite-Lived Intangible Assets [Line Items]
Proceeds from issuance of preferred stock, preference stock, and warrants		$ 150,000
Proceeds from issuance or sale by company of common stock		$ 50,000
Percentage of shares of common stock sold under sales agreement		3%
Number of shares issued in transaction (in shares)	933,500		413,988
Issuance of common stock	$ 8,100		$ 3,000
Aggregate net proceeds		$ 7,600	2,800
Amount remaining under ATM program			$ 38,800	$ 38,800

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands					1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 22, 2024	May 25, 2023	Jul. 30, 2022	Jun. 01, 2021	May 31, 2021	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Deferred revenue						$ 749		$ 749		$ 1,090
Deferred revenue recognized							$ 0		$ 0
Remaining performance obligation						1,900		1,900
Grant period (in years)					5 years
Research and development arrangement with federal government, total budget					$ 9,300
Research and development arrangement with federal government, funding for subawards					$ 5,500
Approved funding, first year				$ 800
Approved funding for subawards, first year				$ 400
Approval for funding, year two			$ 2,600
Approval for funding, subawards, year two			$ 1,600
Approval for funding, year three		$ 3,000
Approval for funding subawards, year three		$ 1,500
Approval for funding, year four	$ 1,700
Approval for funding subawards, year four	$ 1,000
Funding received for costs incurred						400	$ 500	1,400	$ 1,000
Prepaid expenses and other current assets						2,116		2,116		$ 2,737
Additional Funding Agreement Terms
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Compensation earned								3,500
Prepaid expenses and other current assets						$ 300		$ 300

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets:
Money market funds, included in cash and cash equivalents	$ 14,968	$ 16,125
Fixed income mutual fund, included in short-term investments	41,412	48,396
Total	56,380	64,521
(Level 1)
Assets:
Money market funds, included in cash and cash equivalents	14,968	16,125
Fixed income mutual fund, included in short-term investments	41,412	48,396
Total	56,380	64,521
(Level 2)
Assets:
Money market funds, included in cash and cash equivalents	0	0
Fixed income mutual fund, included in short-term investments	0	0
Total	0	0
(Level 3)
Assets:
Money market funds, included in cash and cash equivalents	0	0
Fixed income mutual fund, included in short-term investments	0	0
Total	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value disclosure	$ 0		$ 0		$ 0
Unrealized gain	200,000	$ 100,000	300,000	$ 700,000
Cumulative unrealized loss		400,000		400,000	$ 100,000
Cumulative unrealized net gain	$ 200,000		$ 200,000
Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative unrealized loss		$ 1,100,000		$ 1,100,000

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 4,260	$ 4,090
Work-in-process	1,492	627
Finished goods	6,332	6,497
Total	$ 12,084	$ 11,214

Balance Sheet Components -Sched

Balance Sheet Components -Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 8,967		$ 8,967		$ 8,770
Less: Accumulated depreciation	(7,926)		(7,926)		(7,767)
Property and equipment, net	1,041		1,041		1,003
Depreciation	100	$ 100	159	$ 132
Machinery, equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,609		4,609		4,522
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,932		1,932		1,822
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,426		$ 2,426		$ 2,426

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Payroll and related expenses	$ 7,635	$ 9,655
Inventory purchases	1,478	588
Professional fees	120	30
Other	839	907
Total accrued liabilities	$ 10,072	$ 11,180

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2022	May 31, 2018	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Jun. 30, 2021	May 31, 2019	Aug. 31, 2011
Loss Contingencies [Line Items]
Renewal term	5 years
Operating lease cost			$ 700,000	$ 700,000	$ 2,100,000	$ 2,100,000
Operating lease term			5 years 9 months 18 days		5 years 9 months 18 days
Operating lease percent			8.50%		8.50%
Operating lease, payments					$ 2,100,000	$ 2,100,000
Distribution agreement, initial term	3 years
Distribution agreement, renewal term	1 year
Distribution agreement intention to not renew	180 days
Purchase obligation, to be paid in the next twelve months	$ 2,400,000
Percentage increase in purchase commitment	10%
Purchase commitment, period	2 years
Accrual for contingent liabilities			$ 0		0		$ 0
Pending Litigation
Loss Contingencies [Line Items]
Accrual for contingent liabilities			$ 0		$ 0		$ 0
Minimum
Loss Contingencies [Line Items]
Annual rental payments		$ 2,800,000
Maximum
Loss Contingencies [Line Items]
Annual rental payments		$ 3,300,000
Lease Facility
Loss Contingencies [Line Items]
Face amount								$ 200,000	$ 700,000	$ 900,000

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
2024 (remaining three months)	$ 714
2025	2,942
2026	3,031
2027	3,122
2028	3,215
Thereafter	5,017
Total undiscounted lease payments	18,041
Less: imputed interest	3,808
Total operating lease liability	14,233
Less: current portion	1,800	$ 1,627
Operating lease liability, net of current portion	$ 12,433	$ 13,814

Debt - Narrative (Details)

Debt - Narrative (Details)	1 Months Ended			3 Months Ended		9 Months Ended
	May 31, 2024	Feb. 28, 2023 USD ($) installment	Sep. 30, 2020 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	May 01, 2024	Mar. 01, 2023	Jan. 31, 2023	Dec. 31, 2022	Sep. 24, 2020 USD ($) shares
Debt Instrument [Line Items]
Principal payment number of installment | installment		1
Minimum annual net revenue						$ 70,000,000
Amortization of debt discount and issuance costs						$ 179,000	$ 207,000
Term Loan
Debt Instrument [Line Items]
Face amount			$ 60,000,000
Proceeds from long term debt			50,000,000
Unused borrowing capacity			$ 10,000,000
Interest rate			12.50%
Effective percentage		12.50%		15.50%		15.50%			13.50%
Final maturity extension period	1 year
Redemption fee, percent								10%
Minimum annual net revenue		$ 45,000,000
Backend fee				$ 1,900,000		$ 1,900,000
Amortization of debt discount and issuance costs				100,000	$ 100,000	200,000	200,000
Interest expense				2,200,000	$ 2,200,000	6,600,000	$ 6,300,000
Term Loan | Series B Redeemable Convertible Preferred Stock
Debt Instrument [Line Items]
Backend fee			$ 1,000,000
Warrants outstanding (in shares) | shares												346,823
Warrant liability, noncurrent												$ 600,000
Term Loan | Payment In Cash
Debt Instrument [Line Items]
Interest rate										8.50%	7.50%
Term Loan | Payment in Kind (PIK) Note
Debt Instrument [Line Items]
Face amount				$ 6,000,000		$ 6,000,000
Interest rate										5%	5%
Term Loan | Minimum
Debt Instrument [Line Items]
Effective percentage		15.70%
Term Loan | Maximum
Debt Instrument [Line Items]
Effective percentage									16.80%

Debt - Schedule of Maturities o

Debt - Schedule of Maturities of Long-term Debt (Details) - Term Loan $ in Thousands	Sep. 30, 2024 USD ($)
Debt Instrument [Line Items]
2024 (remaining three months)	$ 1,932
2025	7,666
2026	67,341
Total	76,939
Less: Unamortized debt discount and issuance cost	(441)
Less: Unaccreted backend fee	(1,900)
Less: Interest	(15,332)
Term Loan	$ 59,266

Common Stock (Details)

Common Stock (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Class of Stock [Line Items]
Common stock authorized (in shares)	200,000,000	200,000,000
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Dividends declared cash	$ 0	$ 0
Common stock reserved for future issuance (in shares)	6,861,480	6,733,868
Shares available for future grant under the 2021 Equity Incentive Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	2,215,236	1,314,502
Outstanding options under the 2021 Equity Incentive Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	2,033,992	2,208,341
Outstanding options under the 2023 Inducement Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	380,424	380,424
Outstanding restricted stock units under the 2021 Equity Incentive Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	1,648,539	2,430,803
Common stock available for Employee Stock Purchase Plan
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)	583,289	399,798

Stock-Based Incentive Compens_3

Stock-Based Incentive Compensation Plans - Schedule of Available for Grant (Details) - 2021 Equity Incentive Plan	9 Months Ended
	Sep. 30, 2024 shares
Shares Available for Grant
Shares available for grant, beginning balance (in shares)	1,314,502
Authorized (in shares)	1,391,173
Granted/Awarded (in shares)	(1,073,758)
Cancelled (in shares)	527,313
Withheld for taxes (in shares)	56,006
Shares available for grant, ending balance (in shares)	2,215,236

Stock-Based Incentive Compens_4

Stock-Based Incentive Compensation Plans - Schedule of Stock Option Activity (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2024 $ / shares shares	Dec. 31, 2023 $ / shares shares
Number of Shares
Beginning balance (in shares) | shares	2,588,765
Granted (in shares) | shares	487,654
Exercised (in shares) | shares	(519,314)
Cancelled (in shares) | shares	(142,689)
Ending balance (in shares) | shares	2,414,416	2,588,765
Vested and exercisable (in shares) | shares	1,548,358
Vested and expected to vest (in shares) | shares	2,414,416
Weighted-Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 4.51
Granted (in dollars per share) | $ / shares	12.33
Exercised (in dollars per share) | $ / shares	1.56
Cancelled (in dollars per share) | $ / shares	14.67
Ending balance (in dollars per share) | $ / shares	6.12	$ 4.51
Vested and exercisable (in dollars per share) | $ / shares	4.67
Vested and expected to vest (in dollars per share) | $ / shares	$ 6.12
Weighted Average Remaining Contractual Term (in Years)
Balance	7 years 4 months 13 days	7 years 2 months 1 day
Vested and exercisable	6 years 6 months
Vested and expected to vest	7 years 4 months 13 days

Stock-Based Incentive Compens_5

Stock-Based Incentive Compensation Plans - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		6 Months Ended	9 Months Ended
	Jan. 31, 2024	Apr. 30, 2021	Dec. 06, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, subject to repurchase (in shares)				0		30,211
ESPP discount percent		85%
ESPP, length of offering period		6 months
Common stock reserved for future issuance (in shares)				6,861,480		6,733,868
Unrecognized stock-based compensation expense				$ 16.9
Period for recognition				2 years 2 months 12 days
2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)		580,000
Shares authorized (in shares)	278,234
Number of shares available for grant (in shares)				583,289
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)				94,743	164,710
Period for recognition				2 months 12 days
Cost not yet recognized, amount				$ 0.1
2021 Employee Stock Purchase Plan | Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Offering period			6 months

Stock-Based Incentive Compens_6

Stock-Based Incentive Compensation Plans - Schedule of Restricted Stock Units (Details) - Unvested restricted stock units	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Number of Shares Underlying Outstanding Restricted Stock Units
Unvested, beginning balance (in shares) | shares	2,430,803
Granted (in shares) | shares	586,104
Vested (in shares) | shares	(983,744)
Cancelled (in shares) | shares	(384,624)
Unvested, ending balance (in shares) | shares	1,648,539
Weighted Average Grant Date Fair Value
Unvested, beginning balance (in dollars per share) | $ / shares	$ 6.52
Granted (in dollars per share) | $ / shares	13.45
Vested (in dollars per share) | $ / shares	6.45
Cancelled (in dollars per share) | $ / shares	7.61
Unvested, ending balance (in dollars per share) | $ / shares	$ 8.77

Stock-Based Incentive Compens_7

Stock-Based Incentive Compensation Plans - Schedule of Recognized Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 2,591	$ 2,421	$ 7,679	$ 7,201
Stock options and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	2,462	2,333	7,284	7,010
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	129	88	395	191
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	180	155	539	449
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	816	751	2,421	1,984
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 1,595	$ 1,515	$ 4,719	$ 4,768

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 0	$ 0	$ 0	$ 0

Net Loss per Share Attributab_3

Net Loss per Share Attributable to Common Stockholders - Schedule of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net loss attributable to common stockholders	$ (5,452)	$ (7,257)	$ (21,891)	$ (26,756)
Denominator:
Weighted-average common stock outstanding used to compute basic net loss per share (in shares)	29,444,625	26,017,329	28,863,120	25,532,415
Weighted-average common stock outstanding used to compute diluted net loss per share (in shares)	29,444,625	26,017,329	28,863,120	25,532,415
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.19)	$ (0.28)	$ (0.76)	$ (1.05)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.19)	$ (0.28)	$ (0.76)	$ (1.05)

Net Loss per Share Attributab_4

Net Loss per Share Attributable to Common Stockholders - Schedule of Potentially Dilutive Securities Outstanding (Details) - shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	4,168,792	5,664,776
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	2,414,416	2,984,317
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	1,648,539	2,516,101
Shares committed under ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	105,837	122,451
Unvested early exercised common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total shares (in shares)	0	41,907